are you trying to get me to rethink my Stage III order and the 12cm wg housing I'm eyeing?

Greg

 

Hey Greg,
No, definitely not. My pump is maxed, including the AFC grind etc etc, so I'm pushing about as much fuel as the average guy can get out of these pumps. I imagine pulling the full fuel screw back would be the easy way out of this dilema, but who wants to do that?!! Since today is my birthday, I think I'll treat myself to $50 worth of #2 and spend the day testing and tuning

 

Happy birthday!

Have you done a run with 30psi at 2600 rpm? That bigger wheel is going to need to flow more air mass to stay in its map . . .

Have fun today!

Alec

 

That's the kind of B-day you can injoy!!! HAPPY B-DAY

 

Hey all, thanks for the b-day wishes! Just got back from some testing. I swapped boost gauges, just to eliminate that variable. No change. I took the nut right off the Turbo Master, so the wastegate was basically flopping in the breeze and fully open whenever the engine is running. Same scenario. I went wot in 4th at about 2200 and it eventually built up to 30psi and started to flutter. At this point, I'm at about 2500 and I just left it to the floor and boost kept climbing to 40, fluttering all the way. My turbo shaft probably should have snapped, but there it is...My 12cm has the entire divider cut out and the wastegate hole drilled and enlarged and even with the gate wide open from the get-go, boost seems to keep climbing with no signs of stopping. Just for kicks, I'm going to pick up some copper line and plumb my extra boost gauge into the pyro hole in the manifold to test drive pressure. If it's as out of whack as I think it is, well, I'll just have to burn that bridge when I get to it. I wonder how much boost I'll loose simply with the addition of the powerstroke intercooler this summer? On a side note, I'm proud of my little VE---even at 40psi in 4th @2400 it was still pouring coal like a freight train!!

 

Hey Greg -- does your new housing have an MWE slot? In addition to testing drive pressure, I would be really interested in testing the intake air temp. I think it must be very high, thus reducing the mass flow. Also, if you have hot intake air, and thus lower charge density, it would contribute to your smoke output.

It still doesn't make sense to me that you would be getting surge with 30psi at 2500 rpm, though. Did you try seeing what HTT had to say?

Hope that your having fun -- according to WAMC the weather should be nice out your way today.

 

Yup, all HTT upgrade housings have MAP slots. I know what Paul at HTT would say--the 12cm is too small to run with the 60mm wheel . Of course, the local Bosch dealer said there's no reason to put the 366 spring in my pump either...I admit I'm trying to rob Peter to pay Paul, or however that goes I agree that I've got silly intake temps that aren't helping matters any. My guess is that the 12 simply won't flow the mass the stage III is capable of pushing. I used to see 35-40 all the time with the baby H1C and had no problems, but I'm guessing that was more temperature related, whereas now the boost #'s are more a function of voulme due to the sheer size of the housing/wheel. I know more air is getting packed in there 'cause when she lights off, it's a whole different truck! I'm still not convinced a normal wastegate controller wouldn't pacify the issue to some degree. The TM controller just doesn't seem like it can provide a linear response throughout it's adjustment range....unless there's such a thing as a progressive-rate spring that works in reverse..hehe.

 

actually...I got him to admit otherwise on Tuesday...

we talked for a bit when I was choosing my compressor upgrade (deciding on Stage II or III)...and I mentioned the "warning" on his site that says the 60 wheel should be used with a turbine housing larger than 12cm...

he said he was probably going to remove that from the site, as many people are having good results with the 12/60 combo...

Greg

 

Greg, did you try blocking the WG closed to eliminate that as a variable?

 

Honestly, no I ASSumed that with the locknut as tight as it would go, there was no way the gate would move at 30psi, but I see your point in trying. Did you say you used a deep socket to hold it?

 

Yep. Picked one that the little aluminum bushing would sit on nicely.

 

Thanks for the tip--I guess I'll keep trying After reading about Got...Diesel?'s thread on using the 12cm in his twins setup, I'm determined to make this work untill I get my BHT3B

 

Well, I blocked the wastegate with a socket. Same thing, same level of boost when it occurs. I'm beginning to suspect a boost leak in my crossover pipe, since I had to cut and splice things to get the silicone adapter to work. Heading out to tear into that....

 

I really don't now if i can bring any thing to this discusion but......here gos

a.. if your 12mm housing will still spin the compressor wheel to 30+boost with the waste gate wide open,and i think that it could spin it even......a

I think that if you were to put a bigger housing on, it would boost just as fast /with same or more boost and no flutter.....It would be vary intesting to see just how much pressure the ex. manifold is holding and how much pressure there is when it flutters?

 

I agree if you can overrun the wastegate like that than I bet your drive pressure is much higher than your boost pressure. When I had my wastegate hooked up once it opened that was it for boost. I think you need a much much bigger wastegate hole.